NO122701B - - Google Patents

Description

New 4-substituted dicyclohexyl-peroxydicarbonates for use as oxidizing agents and as polymerization initiators.

The present invention relates to ^-substituted dicyclohexylperoxydicarbonates for use as oxidizing agents and as initiators in the polymerization of polymerizable unsaturated monomers.

Diisopropyl, di-n-butyl and dicyclohexyl peroxydicarbonates are known to be effective as initiators in the polymerization of polymerizable unsaturated monomers. Typical compounds that can be polymerized are those containing vinyl groups, such as vinyl chloride, vinylidene chloride, vinyl bromide, acrylamide, N-substituted methacrylamides, acrylonitrile, vinyl acetate and methyl methacrylate and compounds containing allyl groups, such as allyl acetate and diethylene glycol bis-(allyl carbonate) as well as other polymerizable compounds, such as ethylene. Kfr. at 12 o-27

However, the above-mentioned peroxydicarbonates are affected

the disadvantage that they "decompose" at room temperature and at slightly higher temperatures undergo explosive decomposition. As a result of these special properties, these peroxydicarbonates must be handled, transported and stored in a cooled state.

It has now surprisingly been shown that hitherto unknown ^-substituted dicyclohexyl-peroxydicarbonates of the structural formula: 0 0

R—( ) O—C— 0_0 _ C—0—/ \ R

where R means a cycloalkyl radical with ^ - 8 carbon atoms, an alkyl radical with 3 - 9 carbon atoms, or a cycloalkyl-alkyl radical with a total of 7-12 carbon atoms, of which 5 - 8 in the cycloalkyl ring, the alkyl and cycloalkyl the alkyl radical is attached to the cyclohexane ring via a secondary or tertiary carbon atom, are stable at room temperature so that it is not necessary to coat them or otherwise stabilize them during transport and/or storage.

The new substituted dicyclohexyl-peroxydicarbonates are solids at room temperature, and they can be used as oxidizing agents in the bleaching of flour, as drying agents for linseed oil, wood oil, soybean oil and other oils and as initiators in the polymerization of polymerizable unsaturated monomers containing vinyl groups, so-

such as vinyl chloride, vinylidene chloride, vinyl bromide, acrylamide, N-substituted methacrylamides, acrylonitrile, vinyl acetate and methyl methacrylate or compounds containing allyl groups, such as allyl acetate and diethylene glycol bis-(allyl carbonate) and other polymerizable compounds, such as ethylene.

As initiators in the polymerization of vinyl chloride, the <!>+-substituted dicyclohexyl peroxydicarbonates are more effective in equivalent molar amounts than the peroxydicarbonates used up to now, which is advantageous from an economic point of view. Preferred dicyclohexyl peroxydicarbonates because they are commercially available products and thus economically advantageous are bis-(^-isopropylcyclohexyl)-peroxydicarbonate, bis-(^-tert.butylcyclohexyl)-peroxydicarbonate, bis-(^--tert. amylcyclohexyl)-peroxydicarbonate, bis-C^f-cyclohexylisopropylcyclohexyl)-peroxydicarbonate and bis-(^--cyclohexylcyclohexyl)-peroxydicarbonate.

The <1>+-substituted dicyclohexyl peroxydicarbonates according to the invention can be prepared by reacting the corresponding halogen formates, preferably the chloroformates, with an aqueous, alkaline solution of hydrogen peroxide, preferably an aqueous solution of sodium hydroxide and hydrogen peroxide, preferably by a temperature lower than ^5°C, and isolates the peroxydicarbonate obtained.

The examples 1-5 below illustrate the preparation of the compounds according to the invention.

Example 1

109.2 g of an aqueous 33 wt % NaOH solution was added with stirring to 36.7 g of an aqueous 50 wt % R" 2 O 2 solution and 675 ml of water. The temperature of the mixture was then adjusted to h0°C. It was then added 0.69 ml of a 27% by weight aqueous solution of sodium (7-ethyl-2-methylundecyl-^)-sulphate ("Tergitol" An-M) as emulsifier.

208.1 g of 9^.5%<*>+-tert.cyclohexyl-chloroformate was added dropwise with continuous stirring over the course of *+5 minutes at kO°C and then 7.k g of a 50% by weight aqueous H 2 O 2 - dissolution. Stirring was then continued for <*>+5 minutes at h0°C. After cooling the reaction mixture to room temperature, the peroxydicarbonate formed was filtered off, dried at 30° C. and recrystallized from pentane. 196 g of bis-(^-tert.butylcyclohexyl)-peroxydicarbonate were obtained. The yield: 92% (calculated on the ^-tert.butyl cyclohexyl chloroformate used.

Example 2

In the same way as described in example 1, bis-(*+-tert.amyl-cyclohexyl)-peroxydicarbonate was prepared from .beta.-tert.amylcyclohexyl-chloroformate.

Example

In the same way as described in example 1, bis-(h-isopropyl-cyclohexyl)-peroxydicarbonate was prepared from .beta.-isopropylcyclohexyl chloroformate.

Example h

In the same way as described in example 1, bis-(^-cyclohexylisopropylcyclohexyl)-peroxydicarbonate was prepared from cyclohexylisopropylcyclohexyl chloroformate.

Example 5

In the same way as described in example 1, bis-(^-cyclohexylcyclohexyl)-peroxydicarbonate was prepared from ^-cyclohexyl-cyclohexyl chloroformate.

Data for the peroxydicarbonates produced according to examples 1-5 are listed in the following table.

Example 6

In order to determine their stability, samples of peroxydicarbonates according to the invention and of known peroxydicarbonates were placed in a tube of "Pyrex" glass and maintained at a constant temperature of 30°C using a constant temperature bath.

The decomposition rate of the peroxydicarbonates was measured by determining the content of active oxygen in the sample at given intervals. The obtained data is listed in the following table:

Example 7

The following 'mixture' was used in suspension ion polymerization of vinyl chloride:

It will be seen from the table that when using bis-(^t-tert.butylcyclohexyl)-peroxydicarbonate or bis-(^--tert.amylcyclohexyl)-peroxydicarbonate in the same molar amount and in the same period of time, a higher turnover is achieved than when using diisopropyl peroxydicarbonate or dicyclohexyl peroxydicarbonate. Alternatively, the same turnover can be achieved in the course of a shorter time.

Claims (1)

Derivatives of dicyclohexyl-peroxydicarbonate for use as oxidizing agents and as polymerization initiators, characterized in that they have the general formula: where R means a cycloalkyl radical with 5 - 8 carbon atoms, an alkyl radical with 3-9 carbon atoms, or a cycloalkyl-alkyl radical with a total of 7-12 carbon atoms, of which 5 - 8 in the cycloalkyl ring, whereby alkyl and cycloalkyl the alkyl radical is attached to the cyclohexane ring via a secondary or tertiary carbon atom.